This invention relates in general to an orthodontic appliance for bondable mounting on a tooth including a body and a polymer resin bonding base molded to the body, wherein the base includes an opening for receiving the arm of an auxiliary or a secondary archwire, and also to an orthodontic appliance for mounting on a tooth including a metal orthodontic body and a polymer resin bonding base bonded to the body.
Heretofore it has been well known to provide a bondable orthodontic appliance for mounting on a tooth, wherein the appliance includes a body and a bonding base attached thereto wherein the body includes an opening for receiving an arm of an auxiliary such as an uprighting spring.
It is also well known to provide bondable orthodontic appliances for mounting on teeth, such as brackets with or without vertical openings or slots. In the profession, the demand for brackets with or without vertical openings or slots is about equal.
It has also been well known to provide metal orthodontic brackets having bodies with vertical slots and with laminated mesh bonding pads or bases attached to the bodies. These laminated mesh bonding pads or bases include a shield or foil of metal laminated to a wire mesh by a sintering process wherein the foil at the periphery is turned over the periphery of the mesh. Such pads or bases are then attached to the brackets.
It is also known to investment cast metal brackets with integral bonding pads or bases wherein such brackets would in some instances include vertical slots or openings.
Further, it is also been known to use a plastic base on a ceramic bracket as disclosed in U.S. Pat. Nos. 5,098,288 and 5,263,859 to facilitate removal of a bracket bonded to a tooth. The latter patent also teaches adhesively securing a bracket to a preformed plastic base where aligning grooves formed in the bracket and the plastic pad define an opening for receiving an auxiliary.
It has also been known as marketed by TP Orthodontics, Inc. of LaPorte, Ind., to provide a ceramic bracket having a ceramic body with a vertical opening or slot for receiving an anchoring arm of an auxiliary and having a heat-cured plastic bonding pad molded to the body of the bracket. These brackets are manufactured under the trademark MXi, which is a trademark of TP Orthodontics, Inc. The bodies of these brackets have been provided with and without vertical openings or slots.
With respect to the use of ceramic brackets by orthodontists, the demand for brackets with vertical slots about equals the demand for brackets without vertical slots, as above mentioned. This requires the manufacturer to have molds for making each of the types of brackets in order to satisfy the demand. From time to time new molds need to be made in order to produce quality brackets, and such molds are quite expensive. With respect to the MXi brackets made by TP Orthodontics, after the bracket body is molded, the wafer or plastic bonding base of a polymer resin is then molded onto the bracket. Accordingly, the polymer resin base is added as a bonding pad following the molding of the ceramic bracket body.
The advent of light-cure adhesive for bonding appliances to teeth has greatly benefitted orthodontists in reducing chair time, easing chairside use by eliminating the need to mix two or more components, allowing unlimited working time because the adhesive does not set up until exposed to light. However, unlike chemical cure adhesives, light-cure adhesives do not cure in the dark. Heretofore, most brackets have metal bonding bases, and when using light-cure adhesive, the curing requires directing light at the base/tooth enamel interface. In order to get optimum curing for the strongest possible bond between metal bonding bases, light must be directed toward the mesial, distal, occlusal and gingival edges of the bonding base to cure the exposed edges of the adhesive. However, the adhesive at the center of the base does not cure because light never reaches the center.
The bondable orthodontic appliance of the present invention eliminates the need to form two different appliance bodies having a bonding base or pad attached to the bodies when desired to produce brackets with or without openings or slots extending in any direction opposite to the archwire receiving side of the appliance. More particularly, a slot or opening behind the archwire receiving part of the appliance can be formed in the polymer base molded to the body of the appliance for receiving an arm of an auxiliary or a secondary archwire, whether the appliance is a bracket or a molar tube. Further the bracket may be made of ceramic, metal or plastic. In each case where the body of the appliance is a bracket or a tube, the body of the appliance would be made without any vertical, horizontal or diagonal opening and that opening would then be formed in the polymer base during molding the base onto the body of the appliance. Thus, where brackets would be provided of ceramic material, only a single mold would be needed to make the ceramic bracket body, as where an opening is desired it would be formed in the base. It will be appreciated that one or more openings may be provided to extend vertically, horizontally, or diagonally.
In an orthodontic appliance having a metal appliance body, the invention provides the advantage of only needing to form a single metal body and then thereafter molding an optically clear or translucent bonding pad or base to the body with or without vertical, horizontal or diagonal openings. Since the base is light-permeable, it allows light to reach further under the base to produce a stronger bond. There is no need to illuminate the edges of the base as the light may be directed on top of the base, thereby significantly reducing curing time. Preferably, the bonding face of the base has a meshlike architecture to provide better mechanical interlock.
Additionally, by incorporating a polymer resin bonding pad or base with the metal body of an appliance, and particularly to a bracket or tube where no vertical, horizontal or diagonal slot or opening is needed in the base, the in-out compensation and profile of the bracket or tube is significantly reduced as the bracket or tube body is partially embedded in the polymer resin base rather than being attached on top of the base as when using a metal mesh base. A lower profile substantially reduces the chances of occlusal interference and bond failures, as well as improving hygiene and tissue health. A bondable tube also eliminates the problems associated with tubes mounted on bands. And where light-cure adhesive is used to bond the appliance to a tooth, the polymer resin base being translucent or optically clear, allows the curing light to penetrate beneath the appliance body to enhance the bonding strength.
Further, the number of steps required for making such a bracket or tube with a resin base are substantially less than the number of steps needed to make a bracket or tube with a metal bonding pad or base.
Moreover, the use of an optically clear or translucent polymer base on a bondable metal appliance body reduces the amount of metal exposed thereby greatly improving the cosmetic appeal or aesthetics of the appliance. Finally, when using light-cure adhesive or cement, inasmuch as the bonding base or pad now is either optically clear or translucent, penetration of the curing light between the metal appliance body and the tooth enamel surface is substantially greater thereby substantially increasing the bond strength of the appliance to a tooth. This decreases the possibility of loosening during the treatment process.
According to the present invention, the method employed in making an orthodontic appliance, which includes a body of metal, ceramic or plastic having a buccal/labial archwire receiving side and a lingual side, includes preparing the appliance body and molding a polymer resin bonding base onto the lingual side of the body such that at least part of the body is embedded in the base. At least one opening extending therethrough may be molded in the base for receiving an anchoring arm of an auxiliary appliance or a secondary archwire.
The method of making an orthodontic appliance according to the invention includes the steps of first making an orthodontic appliance body of metal, ceramic or plastic, cleaning the surface of the appliance body where needed, subjecting the body to an adhesion-promoting process, and then molding either a light-curable or heat-curable polymer resin bonding base onto the lingual side of the body that may have at least one opening extending through the body thereby defining a one-piece orthodontic appliance. The polymer resin base may be acrylic, epoxy, or epoxy/acrylic in the form of an acrylic-based epoxy, and which is either light curable or heat curable.
Another embodiment of the invention is to form the orthodontic appliance of an appliance body and a polymer resin bonding base molded onto the body, and providing the appliance body and bonding base with matching grooves that coact to form a vertical slot or opening.
It is therefore an object of the present invention to provide an orthodontic appliance of the bracket or tube type from a standard bracket or tube appliance body and a polymer resin base with or without openings in the base to thereby reduce manufacturing costs associated with making one appliance without openings and another with openings.
Another object of the present invention to provide an orthodontic appliance including an appliance body of metal, ceramic or plastic and a heat or light-curable polymer resin bonding base molded onto the body and having at least one opening extending therethrough for receiving an arm of an auxiliary appliance or a secondary archwire.
A further object of the present invention is to provide an orthodontic appliance including an appliance body and a polymer resin bonding base molded to the body having at least one opening through the base for receiving an auxiliary or a secondary archwire.
A still further object of the present invention is to provide an orthodontic appliance having a metal appliance body and a polymer resin bonding base molded to the body that reduces the in-out compensation and the profile height of the appliance, and wherein the polymer resin bonding base may be optically clear or translucent to enhance the aesthetics of the appliance.
A still further object of the present invention is to provide an orthodontic appliance having a metal appliance body and a polymer resin bonding base molded to the body that reduces the in-out compensation and the profile height of the appliance, and wherein the polymer resin bonding base may be optically clear or translucent to increase the bond strength when bonded to a tooth with a light-cure adhesive.